Preparing a functionalized thermoplastic elastomer—bromination and synthesis of poly(p-methylstyrene-co-styrene)-block-poly(ethylene-co-butene)-block-poly(p-methylstyrene-co-styrene)

✍ Scribed by Cheng-Ying Tsai; Chih-Ping Huang; Raymond Chien-Chao Tsiang

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 181 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19991115)37:22<4108::aid-pola9>3.0.co;2-2

✦ Synopsis

A poly(p-methylstyrene-co-styrene)-block-poly(ethylene-co-butene)-blockpoly(p-methylstyrene-co-styrene) thermoplastic elastomer was prepared via anionic synthesis of poly(p-methylstyrene-co-styrene)-block-polybutadiene-block-poly(p-methylstyrene-co-styrene) followed by a hydrogenation of the polybutadiene midblock. The sequential method used for the synthesis has resulted in a nearly monodispersed polymer with a polydispersity of 1.03. Bromination of such synthesized copolymer was next, conducted using two different methods. In the presence of a FeCl 3 catalyst in CCl 4 solvent, bromination occurred through forming a carbocationic complex to undergo an electrophilic substitution reaction on the aromatic rings of the end blocks. Nevertheless, the bromination occurred exclusively on the p-methyl groups of the end blocks when conducted in cyclohexane using photoinitiated free radicals. The microstructure of the brominated molecules were analyzed using 1 H-NMR and 13 C-NMR, and bromination efficiencies of 48 and 44% have been attained from the two methods, respectively.